The hypothesis we will test is whether in hypoalphalipoproteinemia, a metabolic state associated with a high prevalence of premature CVD, there is a structural and functional abnormality of plasma HDL attending the low levels of plasma HDL. We will study the post-prandial response of HDL and related parameters inclusive of Lp(a) to a single meal containing at each time different types of fats (saturated vs. omega-6 polyunsaturated vs omega-3 polyunsaturated fatty acids).